Effect of Cerium on Characteristic of Inclusions and Grain Boundary Segregation of Arsenic in Iron Melts

Abstract

In order to depress the embrittlement induced by grain boundary segregation of arsenic in steel, the effect of Ce addition on the formation of arsenious inclusions and arsenic concentration at grain boundaries were systematically investigated in iron melts. The results showed that different types of arsenious rare earth inclusions were formed with different Ce content. As Ce content increased from 0.037 to 0.095 wt%, the dominant inclusion in the melt was changed from the Ce-S-O inclusion fully coated by Ce-S-As inclusion to the Ce-S-As inclusion completely covered by Ce-As inclusion. Simultaneously, the single Ce-S-As and Ce-As inclusions were also detected when Ce content was more than 0.055 wt%. The amount and average size of inclusions increased with increasing Ce content. Transmission electron microscope analysis indicated that the Ce-As inclusion was the CeAs phase, which was formed during solidification process. Furthermore, concentration of arsenic on grain boundaries after adding Ce was decreased to the level of the matrix.